Conventionally, when a beverage container is used, the inside of a cylindrical container body is sterilized, and then the container body is filled with the beverage and sealed with a lid.
A typical lid of the so-called peelable-seal type (membrane type) comprises a sheet of aluminum foil laminated with a stretched film of PET (polyethylene telephthalate) having an easy-to-peel layer for facilitating peeling operation which is formed on the surface of the lid to be in contact with the container body. The lid covers and seals the top opening of the container body.
Another type of lid has an opening-for-drinking formed in the lid body, and the opening-for-drinking is covered with a pull-tab comprising PET and aluminum foil and having an easy-to-peel layer, wherein the pull-tab and the periphery of the opening-for-drinking are sealed together.
However, when the conventional peelable-seal type lid is used, the sealing force between the lid and the container body must be set to be strong enough to prevent the lid from detaching from the container body during transportation, while the sealing force must be set to be weak enough to afford easy peeling of the lid from the container body to open the container. Therefore, setting a proper sealing force to achieve a balance between those two requirements is not easy.
In addition, when the lid is removed from the container body to open the container, the opening-for-drinking may become too large and the contained beverage may spill easily.
On the other hand, when the lid with a pull-tab for sealing is used, because an easy-to-peel layer is formed on the pull-tab, the appearance of the lid no longer gives an impression of high quality.
Accordingly, there may be employed another type of a lid wherein an opening-for-drinking is formed on the lid body and is covered and sealed with a pull-cap. In that case, the sealing force between the lid and the container body may be made strong enough, and the sealing force of the pull-cap may be made weak enough, so that the lid may not detach from the container body during transportation, and easy opening of the beverage container may be afforded.
Moreover, the opening-for-drinking does not become too large, and the appearance of the lid gives an impression of high quality.
However, after the pull-cap is removed to open the beverage container, the pull-cap is sometimes thrown away without consideration, thereby causing environmental pollution.
The object of the present invention is to solve the above-mentioned problems of the conventional lids and to provide a lid that will not detach from the container body during transportation, that affords easy opening of the container, whose opening-for-drinking does not become too large, whose appearance gives an impression of high quality, and that does not cause environmental pollution.